The fabrication of novel Cu2(NO3)(OH)3/g-C3N4 catalyst for the thermal decomposition of ammonium perchlorate

Abstract

A novel Cu₂(NO₃)(OH)₃/g-C₃N₄ catalyst (BCN:MCN) is synthesized via a facile urea-assisted hydrothermal precipitation method for enhancing the thermal decomposition of ammonium perchlorate (AP). The as-fabricated BCN/MCN (1:1) catalyst exhibited superior catalytic activity than CuO, which reduced the high-temperature decomposition (HTD) peak of AP from 424.5 °C to 315.9 °C. The results of characterizations revealed that the introduction of MCN supports suppressed the crystallization of CuO and contributed to the deposition of block copper-based BCN on its surface, and the morphology of composite catalyst could be regulated by controlling the ratio of Cu(NO₃)₂·3H₂O and urea. Notably, the flower-like BCN nanostructures were uniformly anchored on the MCN surface in the BCN/MCN (1:1) composite catalyst, which displayed a larger BET surface area (6.0 m²/g) and pore volume (0.019 cm³/g) than CuO catalyst. Furthermore, the incorporation of BCN enriched surface Cu⁺ species and elevated the active oxygen ratio (O_β/(O_α+O_β+O_γ) to 60.2 %, thereby synergistically enhancing the redox activity of composite catalyst. Finally, kinetic studies demonstrated a 27.5 % reduction in activation energy (E_a) of AP thermal decomposition (from 194.9 kJ/mol to 141.3 kJ/mol) with 2 wt% BCN/MCN (1:1) loading, attributed to the accelerated electron transfer and nitric acid-assisted NH₃ oxidation, and a proton-electron transfer mechanism was proposed for AP thermal decomposition under the action of Cu₂(NO₃)(OH)₃/g-C₃N₄ catalyst.